Automatic door closer, especially loft door closer

ABSTRACT

914,660. Door closers. MANKEL, R. Feb. 2, 1961 [March 10, 1960], No. 4039/61. Class 65 (1). A door closer comprises a casing 10 containing a coil tension spring 27 and a pivotally-mounted hydraulic piston and cylinder brake 31, 32, the closing shaft 14 which is rotatably mounted in the casing having a crank 19 connected by a linkage system 20, 22 to a rocking lever 24 engaged by both the spring and the brake. In the region of the crank 19 the closing shaft 14 is reduced in diameter so that only a portion 42 remains, and the link 22, which is pivoted to the link 20 at 21, comprises two parallel webs each having a bent lug 26 adapted to engage the link 20 to act as a stop. When the door (not shown) is closed the links are approximately aligned (Fig. 5) and they remain so until the door has opened about 60 degrees when the link 20 abuts a surface of the shaft portion 42 (Fig. 6), subsequent opening of the door then causing the linkage to bend about its pivot 21 until the 180 degrees open position is reached (Fig. 8) when the link 22 also abuts the shaft portion 42 and arrests the opening movement. In this position the pin 23 by which the spring 27 is connected to the rocking lever 24 is so disposed relative to the linkage 20, 22 and the closing shaft that the closing torque is reduced to zero. When the door is released from this position it begins to close under the action of the spring 27 and during the closing movement the link 22 rotates in an anti-clockwise direction relative to its pivotal connection 23 with the rocking lever 24. As soon as the 60 degrees position is reached (Fig. 6) the link 20 commences to rotate in a clockwise direction relative to the crank 19, and the friction at the pivots 19, 23 is arranged to be sufficient to cause the linkage, in spite of the tension caused by the spring 27, to pass slightly over-centre until the stops 26 on the link 22 abut the link 20. By this means the linkage forms a rigid strut so that if the door should be forced manually towards the closed position after the brake has come into action there is little risk of the linkage collapsing. An abutment surface 45 is formed on the casing to limit such collapse if, through unfavourable circumstances, it should occur. A bore 39 is formed in the wall of the brake cylinder 32 so that braking action occurs only shortly before the piston 31 has finished its inward stroke, the braking action being adjustable by means of a valve 35 which may contain a heat-sensitive insert to adapt the area of the valve passage to the temperature-responsive viscosity of the hydraulic fluid. A pressure relief valve 34 with an adjustable spring and a non-return valve 38 are also provided. A spring-loaded pin 41 (Fig. 3, not shown), projecting from the top of the casing near the shaft 14 may be provided to engage a recess in the lever arm carried by the extension 15 of the shaft to hold the door in a predetermined open position. Alternatively (Fig. 4, not shown), notches may be formed on the edge of the link 20 which cooperate with a spring-loaded pin inside the casing. Specification 778,850 is referred to.

H. BOMM AUTOMATIC DOOR CLOSER, ESPECIALLY LOFT DOOR CLOSER 2 Sheets-Sheet 1 Filed Feb. 9, 1961 F/Gil" FIG. 2

INVENTOR.

Wei/22: 80mm iclzauzl 9- Oct. 29, 1963 H. BOMM 3,108,315

AUTOMATIC DOOR CLOSER, ESPECIALLY LOFT DOOR' CLOSER Filed Feb. 9, 1961 2 Sheets-Sheet 2 FIG 5 FIG. 6

INVENmR W s, W

United States Patent 3,168,315 AUTOMATHQ DGQR QLGSER, ESPECTALLY LOFT 300R CLQSER Heinz Bomm, Enncpetal-Voerde, Westphalia, Germany, assignor to Dorken c Mankel K132, Ennepetal-Voerde, Westphalia, Germany, a firm Filed Feb. 9, 1961, Ser. No. 88,151 Claims priority, application Germany Mar. 10, 1961) 14 Claims. (Cl. 16-55) This invention relates to door closers, and more specifically to an automatic door closer suitable for use as a loft door closer.

Door closers have already become known in which a rocking lever is mounted at one end in a casing and engaged at its free end by a piston rod of a piston-cylinder-arrangement pivotally mounted in the casing and braking the closing movement of the door. In the easing there is also accommodated a coil pressure spring which with one of its ends facing the rocking lever is supported on a stop fixed in the casing and with its other end engages a lever pivotally mounted in the casing and connected to the rocking lever by means of a couple. This arrangement requires a relatively large space and leads to a complicated construction. Furthermore, the spring is not accessible from outside so that its pro-tension determining the closing torque cannot be varied without difficulty. Moreover, the spring requires a guiding arrangement which prevents an outward bendmg.

In other known loft door closers, two tension springs are connected in parallel by means of a movable yoke which is coupled to a rocking lever fixedly mounted at one of its ends to the casing. This rocking lever in turn is connected to a crank of a closing shaft by means of a link system comprising two links connected in series. In this form of construction, a stationary piston-cylinderarrangement is disposed between the two springs. The piston is directly connected by means of a connecting rod to a crank formed by a bend of the closing shaft. This door closer also requires a considerably large space and is not reliable in operation since the two springs must be adjusted to equal pro-tensions to ensure a satisfactory operation. This adjustment, however, cannot be effected from outside. The arrangement is such that the closing spring only exerts a torque acting in the closing direction, when the, opening angle is below 90.

It is the object of the present invention to provide an automatic door closer which ensures positive operation, has small dimensions and contains only few structural elements which can easily be manufactured, the preatension of a spring determining the closing torque being adjustable from outside.

This object is achieved by providing an automatic door closer, especially loft door closer, which comprises a casing, a coil tension spring arranged in said casing to act in the closing direction of the closer, a hydraulic piston-cylinder-arrangemenrt pivotally mounted adjacent said coil tension spring and adapted to act as a brake device, a rocking lever pivotally mounted at one of its ends and operable by both said coil tension spring and said piston-cylinder-arrangement, a closing shaft rotatably mounted in the casing and having a crank, and a link system connecting the crank of the closing shaft with the rocking lever, said rocking lever being engaged, additionally to the piston-cylinder-arrangement and the link system, by one end of said coil tension spring facing said rocking lever.

The fact that the rocking lever is engaged, additionally to the pis-ton-cylinder-arrangement, by the end of the coil tension spring facing it, alfords the advantage over the aforementioned known constructions of door closers that links for the link system and the space required therefor are saved and that one end of the coil tension spring can readily be supported by the wall of the casing of the door closer in such a manner that the pre-tension of the coil tension spring is adjustable from outside and a relatively great spring expansion is available. The cross-sectional dimensions of the spring can therefore be kept relatively small. This permits the casing to be constructed of small depth so that its accommodation in a door will not cause any difficulties even under unfavourable circumstances.

The invention may 'be embodied in various ways. In a preferred embodiment, the coil tension spring is connected to the free end of the rocking lever and the pistoncylinder-arrangement is connected to the rocking lever intermediate the ends thereof. Moreover, the forces exerted by the coil tension spring can easily be adapted to the closing torques expedient for the individual opening positions of the door. In order to obtain also a relatively long stroke for the piston of the hydraulic piston-cylinder-arrangement constituting a brake device and thereby to obtain a favourable diameter of the cylinder, it is advisable to couple, according to another feature of the invention, the piston movable in the pivotally mounted cylinder to the rocking lever by means of a pivot displaced towards the free end of the rocking lever in relation to the longitudinal axis of the piston. In this case a relatively short rocking lever already meets the requirements so that the width of the casing of the door closer can be kept small. The casing requires only an inside width which slightly exceeds the total of the diameters of the coil tension spring and of the cylinder of the piston-cylinder-arrangement located adjacent thereto.

An important feature of the invention consists in that the piston may be provided with an extension which extends at an acute angle in relation to the longitudinal axis of the piston and establishes the connection of the piston with the rocking lever. This results in a simple construction which nevertheless meets all requirements.

It has proved expedient to arrange the pivot establishing a hinged connection of the piston with the rocking lever so as to be displaced in relation to the longitudinal axis of the piston by about the radius of the piston. Then, also in the case of a relatively small length of the piston, the guiding forces acting on one side are still reliably taken up. It would, however, easily be possible to displace the pivot even more in relation to the longitudinal axis of the piston to obtain a particularly great piston stroke and thus a small diameter of the piston.

The link system establishing the connection of the rocking lever with the crank of the closing shaft expediently engages the free end of the rocking lever. This permits the forces to be Well adapted to the required torques in a simple manner.

According to another feature of the invention, the rocking lever may consist of two parallel Webs and receive between the webs, intermediate the ends thereof, the end of the extension of the piston, and, on its free end, the end of the coil tension spring by means of a threaded pin which also connects the link system establishing the connection with the crank of the closing shaft and engaging around the rocking lever with a forked junction end. This results in a space-saving assembly of elements which can easily be manufactured.

"If about are suflicient for the closing angle of the door which is determined by the energy stored in the coil tension spring of the door closer, the link system may be replaced by only one link rigid in itself and known per so. If, however, an opening angle of the door of up to about is intended to be obtained, through which angle the door is desired to automatically close, it is advisable, according to a further feature of the invention, to form the link system establishing the connection between the rocking lever and the crank of the closing shaft, of two hingedly series-connected links which assume substantially aligned positions during the braked closing operation. The links are connected by a pivot which allows free swinging movements of the door but is secured against a substantially passing of the links past the aligned positions by stops on the links of the link system. Such a link system can advantageously be used, if desired, in door closers of different construction. The very simple construction designed for a working range of up to about 180 is based on the idea that the two-membered link system, in the basic construction of the door closer according to the invention, due to the friction occurring in its connecting bearing, tends to pass, when the door is being closed, from a bent position corresponding to a wide opening position of the door past the aligned position into a bent position directed to the other side. The aligned position, however, cannot substantially be passed on account of the stop arrangement provided in the region of the pivot connecting the links of the link system. Therefore, it is practically sufficient for the pivot connecting the links of the link system to be stabilized only in one direction by means of said stop arrangement, without running the risk of the link system bending outwardly towards the side remote from the closing shaft. This is essential when, as it is conventional practice, only in the last phase of the closing movement the door is subjected to the braking action of the hydraulic piston-cylinder-arrangement, for, in this case, forces acting in the closing direction might be exerted on the door, which would subject the link system to pressure load. Experience has shown that also in this case there is no risk of the link system bending outwardly towards the side remote from the closing shaft. To absolutely reliably exclude also under unfavourable operating conditions, for example in the case of vibrations of the building or the like, the undesirable outward bending of the links of the link system towards the side remote from the closing shaft when the link system is subjected to pressure, provision can be made, according to another feature of the invention, of a stop surface which is formed on the casing wall and prevents the link system from substantially bending outwardly towards the side remote from the closing shaft. Such a stop surface will hardly ever be required in practice, but it also affords under unfavourable circumstances a reliable protection against defective motional actions.

As it has already been stated, the movement of the links of the link system past the aligned position into a bent position situated closely adjacent the aligned position and supported by stops, which stabilizes the pivot connecting the links of the link system, is brought about sufficiently reliably by the friction existing in the pivotal ranges of the link system. According to still another feature of the invention, a greater reliability can be obtained by coordinating a brake, such as a friction brake or the like, with at least one of the connecting pivots of the two-membered link system.

If it is intended to automatically hold the door in selected opening positions, a locking means for holding the door in predetermined opening positions may be provided to act upon the link of the link system coupled to the crank of the closing shaft. In a rather simple construction of such an arrangement, the link coupled to the crank of the closing shaft is equipped with locking stops, such as notches or the like, which correspond to predetermined opening positions of the door and cooperate with a springloaded locking member, such as a locking pin or the like, mounted in the casing. Moreover, such a locking device may also be constructed as a safety stop to prevent an unintentional outward bending of the links of the link system subjected to pressure and being substantially in the aligned positions.

The structural shape of the link system and of the parts cooperating therewith may vary. The crank of the closing shaft may be formed of two webs which are interconnected by means of a crankpin connecting the associated link of the link system. Furthermore, the link of the link system coupled to the rocking lever may be composed of two parallel webs. in such a form of construction the stop arrangement, by means of which the pivot connecting the links of the link system is stabilized in one direction of movement substantially in the aligned positions of these links, can be formed in a particularly simple manner by providing the link of the link system coupled to the rocking lever with bent-off lugs on an end portion projecting beyond the pivot which establishes the connection with the link of the link system coupled to the crank of the closing shaft. These bent-off lugs engage the link of the link system coupled to the crank of the closing shaft after the aligned positions of the links of the link system have been passed in the direction of the closing shaft. The stop position is intended to be situated closely adjacent the aligned positions of the links of the link system.

The arrangement of the individual pivots provided in the door closer may be adapted to the actual requirements. In a closer of a door which can be turned through an angle of up to 180, the rocking lever extends, in the closed position of the door, at an angle of about 45 in relation to the link system. It is also expedient that in the closed position of the door the rocking lever extends at an angle of about in relation to the longitudinal direction of the coil tension spring and the piston-cylinderarrangement, respectively. This space-saving arrangement results in a particularly adantageous relationship of forces.

It has already been mentioned that predetermined opening positions of the door can be locked with the aid of the link coupled to the crank of the closing shaft. Instead of or in addition to this, it is, however, also possible to arrange, in the casing of the door closer, a substantially vertically movable spring-loaded locking pin which projects freely from the casing and cooperates with a closing arm mounted on the closing shaft, for locking an opening position of the door. Such a locking device can also advantageously be used in other loft door closers.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a sectional view of a loft door closer according to the invention, taken on line I-I of FIG. 2;

FIG. 2 is a top plan view of the loft door closer with removed cover plate;

FIG. 3 is a sectional view of the loft door closer taken on line IIIIII of FIG. 2;

FIG. 4 is a fragmentary top plan view of a modification of part of the arrangement shown in FIGS. 1 and 2 which serves for locking predetermined opening positions of the door, and

FIGS. 5 to 8 are sectional views of essential parts of the door closer in different opening positions.

Referring now to FIG. 1, a loft door closer according to the invention has a casing 10 of substantially quadrangular cross-section and closed at its upper side by a screwed-on cover plate 11, a flat gasket being disposed therebetween. The casing 10 is preferably a cast piece. A closing shaft 14 is mounted for rotation in two antifriction bearings 12 and 13 mounted in the casing 10 and has a portion which projects from the casing and carries in a known manner an extension 15 having a square cross-section and serving for fitting a lever thereto. The shaft 14 has a neck portion which is surrounded by a bushing 17 containing a gasket 16 and mounted in the cover plate 11. The shaft 14 carries between the anti-friction bearings 12 and 13 two crank webs 18 which are interconnected by a crankpin 19 coupled to a link system. This link system comprises a link 20 mounted on the crankpin l9 and a link 22 consisting of two parallel webs hingedly connected to the link 26 by means of a pivot 21, as can be seen from FIG. 2. The link 22 of the link system establishes the connection to a threaded pin 23 serving as a pivot. The two webs of the link 22 rest both on the link 2d of the link system and on the free end of a rocking lever 24- which also consists of two webs and is pivotable about a pin 25 fixedly mounted in the casing 19. The two webs of the link 22 of the link system each have a bent-oh lug 26 which acts as a stop engaging the outer surface of the link 2t shortly after the links 243 and 22 of the link system have moved in upward direction out of their aligned positions so as to prevent these links from shifting in downward direction out of their substantially aligned positions. A coil tension spring 27 has one end which faces the rocking lever 24 fixed between the two webs of the rocking lever by means of the threaded pin 23, and the other end mounted on a screw member 28 which extends through one of the end walls of the casing and is turnably mounted therein in a sealed condition. This screw member 2% enables the pro-tension of the coil tension spring 27 to be adjusted from outside. The threaded pin 23 extends through both webs of the rocking lever 24 at the free end thereof. Intermediate the ends of the rocking lever 24 the free end of an extension 3d of the piston 31 of a piston-cylinder-arrangement is hingedly connected to the rocking lever 24 by means of a pivot 29, and the cylinder 32 of the piston-cylinder-arrangement is pivotally mounted at the base of the casing 1% on a pin 33 fixedly mounted in the casing. The extension 3%? of the piston 31 extends at an acute angle towards the free end of the rocking lever 24 in relation to the longitudinal axis of the piston so that the pivot 29 of the extension 36) is located relatively closely adjacent the threaded pin 23 of the coil tension spring 27. As shown in FTG. 1, the bottom of the cylinder 32 of the piston-cylinder-arrangement serving as a hydrauiic brake device contains, in addition to a relief pressure valve 34 with an adjustable spring, an adjustable valve 35 determining the braking action. Both valves are connected to a working chamber 36 of the piston-cylinderarrangement by means of a channel 37. In the valve 35 there can be mounted an insert sensitive to heat which adapts the cross-sectional area of the passage of the valve 35 to the temperature responsive viscosity of the brake fluid. In the bottom of the cylinder 32 a nonreturn valve 35 (FIG. 2) is arranged which permits brake fluid to flow into the working chamber 36 of the piston-cylinderarrangernent when a door with which the door closer is associated is being opened. A bore 3) is provided in the wall of the cylinder 32 and is closed or opened in dependence upon the position of the piston fill, the arrangement being such that a braking action occurs only shortly before the piston has finished its inward movement, whereas before that condition has taken place the fluid within the working chamber 36 of the piston-cylinder-arrangement can escape through the bore 39 without opposing appreciable resistance to the inward movement of the piston.

As shown in FIG. 3, a freely projecting locking pin 41 loaded by a spring 445 can be provided in the casing it) near the shaft 14, which pin 41, when cooperating with a locking recess in the lever fitted to the extension of the shaft 14, secures the door in a predetermined unlocked position.

As can be seen from FIGS. 5 to 8, the shaft 14 is reduced in diameter in the region between the crank Webs 18 by removing material from the shaft to such an extent that only a shaft portion 42 remains.

The mode of operation of the door closer according to the invention will now be explained with reference to FIGS. 5 to 8. As shown in FIG. 5, in the locked position of the door corresponding to the positions of the parts of the door closer shown in FIGS. 1 and 2, the rocking lever 2 extends at an angle of about in relation to the longitudinal axis of the coil tension spring 27 and the piston-cylinder-arrangement 31, 32. The links 20 and 22 coupled by the pivot 21 and forming the link system between the rocking lever 24 and the crankpin l? are approximately aligned, the bent-off lugs 26 of the link 22 of the link system engaging the outer surface of the link 2%. When the door is opened, the links 2i and 22 are first maintained in their aligned positions, i.e., only the rocking lever 24 is turned in anticlockwise direction. This causes the coil tension spring 27 connected to the rocking lever 24 by means of the threaded pin 23 to be further tensioned while the piston 31 in the cylinder 32 is drawn outwardly. During this action brake fiuid flows into the working chamber 36 of the piston-cylinderarrangement 31, 32 through the nonreturn valve 33. After a pivotal movement of the door through about 60, as shown in FIG. 6, the link 20 of the link system engages with its edge facing the shaft 14 a surface of the shaft portion 42, so that, upon further pivotal opening movement of the door in the direction of arrow 43, the link system 267, 22 is bent in the region of the pivot 21, the bent-off lugs 26 of the link 22 of the link system moving off the link 26 of the link system. As the door continues to turn past a 90 position, shown in FIG. 7, the rocking lever 24 is moved further in anticlockwise direction. When finally the door has reached an opening angle of as shown in FIG. 8, the link 22 of the link system also engages a coordinated surface of the portion 42 of the shaft. In this position the closing torque is reduced to zero.

During the pivotal opening movement the coil tension spring 27 has been tensioned by means of the rocking lever 24- and has reached its greatest tension in the 180 opening position of the door. When the door is released, the coil tension spring 27 retracts the rocking lever 24 in clockwise direction by its force acting in the direction of arrow 44, so that the positions shown in FIGS. 7 and 6 are passed successively. During this action the brake fluid within the working chamber 36 of the piston-cylinderarrangement 31, 32 can still escape substantially without hindrance through the bore 39 provided in the wall of the cylinder 32 as this bore is not covered by the piston 31. In this 60 position of the door shown in FIG. 6, the links 20 and 22. of the link system are again aligned. For further return movement under the action of the coil tension spring 27, the link 20 of the link system must turn in clockwise direction relative to the crank Webs 18 and the crankpin 19, whereas the link 22 of the link system turns in anticlockwise direction relative to the rocking lever 24. Due to the friction occurring in the bearings of the crankpin 1 and the threaded pin 2.3, the link system passes, in spite of the tensile stress, from the aligned position into a bent position which is situated closely adjacent the aligned position and is stabilized by the bent-off lugs 25 of the link 22 of the link system engaging the outer surface of the link 20 of the link system. In this bent position the pivot 21 is, as compared with FIG. 6, displaced slightly upwardly in relation to a straight line passing through the central points of the crankpin 19 and the threaded pin 23. This results in a condition which prevents the lever system from bending outwardly in downward direction, that is to say that the pivot 21 is prevented from passing into a position located below the straight line passing through the central points of the crankpin 19 and the threaded pin 23. Thus, even if an outer force subjecting the links 26 and 22 of the link system to pressure is exerted on the door in the closing direc tion after the braking action of the piston-cylinder-arrangenient has been initiated by the bore 39 having been closed by means of the piston 31, there is no risk of the link system bending outwardly. If such an outward bending should nevertheless occur owing to unfavourable circumstances, an abutment surface 45 (FIG. 6) formed on 7 the casing wall limits this movement even after a slight out-ward bending.

Referring to the embodiment shown in FIG. 4, which may correspond as regards the other parts of the door closer to the construction already described, a link 46 is used instead of the link 2%) of the link system, which has on its outer surface locking notches 47 and 43 which cooperate with a spring-loaded locking pin 4-9 longitudinally slidable in the casing. This arrangement permits the door to be locked in the desired positions. Moreover, such a locking arrangement may also be constructed as a guide surface keeping an unintentional outward bending of the pressure-loaded link system within safe limits.

The invention may be embodied in other specific forms Without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. For example, additional friction members may be provided in the region of the crankpin 19 and the threaded pin 23 to reliably transfer the pivot 21 into a position beyond a straight line passing through the crankpin 19 and the threaded pin 23, in which position the link system is stabilized by the bent-off lugs 26 of the link 22 of the link system. The stop arrangement stabilizing the two-membered link system in the connecting joint of the two links in one direction of movement may be modified in various Ways over the embodiment described. For example, stops may also be provided on the broadsides of the links of the link system. The spatial arrangement, especially of the pivots fixedly mounted in the casing may be modified. The brake device formed by the pistoncylinder-arrangement may be constructed in a known manner so that a braking action increasing progressively to Wards the locking position of the door occurs. The bore 39 provided in the wall of the cylinder 32 may be so dimensioned that a certain closing speed cannot be exceeded already during the initial closing movement of the door.

I claim:

1. An automatic door closer comprising, in combina tion, housing means; rotary crank means supported for rotation about its axis by said housing means, said crank means being adapted to be connected to a door and turning in a door-opening direction during opening of the door and in a door-closing direction during closing of the door; an elongated rocking lever pivotally carried adjacent one end thereof by said housing means for turning movement about an axis parallel to that of said rotary crank means, said rocking lever having a free end portion distant from said one end thereof connected to said housing means; linkage means connected at one end to said rotary crank means and at an opposite end to said rocking lever for turning the latter in an opening direction during turning of said crank means in said door-opening direction and in a closing direction during turning of said crank means in said door-closing direction; an elongated coil spring connected to one end to said rocking lever at said free end portion thereof and at an opposite end to said housing means and said coil spring being tensioned during turning of said lever in said opening direction so that said coil spring urges said rocking lever to turn in said closing direction to act through said linkage means on said crank means for urging the latter to turn in said door-closing direction after the door is opened; and elongated damping means for damping the closing of the door by said coil spring, said elongated damping means being located alongside of and closely adjacent to said coil spring, being pivotally connected to said rocking lever between the ends thereof so that the coil spring is connected to said rocking lever at a location more distant from the turning axis thereof than said damping means, and said damping means being connected to said housing means at a part of said damping means spaced from said rocking lever.

2. An automatic door closer comprising, in combination, housing means; rotary crank means supported for rotation about its axis by said housing means, said crank means being adapted to be connected to a door and turning in a door-opening direction during opening of the door and in a door-closing direction during closing of the door; an elongated rocking lever pivotally carried adjacent one end thereof by said housing means for turning movement about an axis parallel to that of said rotary crank means, said rocking lever having a free end portion distant from said one end thereof; linkage means connected at one end to said rotary crank means and at an opposite end to said rocking lever for turning the latter in an opening direction during turning of said crank means in said door-opening direction and in a closing direction during turning of said crank means in said doorclosing direction; an elongated coil spring connected at one end to said rocking lever at said free end portion thereof and at an opposite end to said housing means and said coil spring being tensioned during turning of said lever in said opening direction so that said coil spring urges said rocking lever to turn in said closing direction to act through said linkage means on said crank means for urging the latter to turn in said door-closing direction after the door is opened; and elongated damping means for damping the closing of the door by said coil spring, said elongated damping means being located alongside of and closely adjacent to said coil spring, being pivotally connected to said rocking lever between the ends thereof so that the coil spring is connected to said rocking lever at a. location more distant from the turning axis thereof than said damping means, and said damping means being connected to said housing means at a part of said damping means spaced from said rocking lever, said damping means including a cylinder connected to said housing means and a piston slidable in said cylinder and having an elongated piston rod connected to said rocking lever at a portion thereof located between said free end portion of said lever and the intersection of the axis of said piston and cylinder with said (rocking lever so that the stroke of said piston is greater than the stroke would be if said piston rod were connected to said rocking lever at said intersection.

3. An automatic door closer as recited in claim 2 and in which said cylinder is pivotally connected to said housing means and said piston rod has its portion which is connected to said rocking lever extending at an acute angle with respect to the axis of said piston and cylinder.

4. An automatic door closer as recited in claim 2 and in which said cylinder is pivotally connected to said housing means and said piston rod has its portion which is connected to said rocking lever extending at an acute angle with respect to the axis of said piston and cylinder, the distance between said intersection and the connection of said piston rod to said rocking lever being equal approximately to the radius of said piston.

5. An automatic door closer comprising, in combination, housing means; rotary crank means supported for rotation about its axis by said housing means and adapted to be connected to a door for turning in a door-opening direction during opening of the door and in a door-closing direction during closing of the door; an elongated rocking lever pivotally connected at one end thereof to said housing means for turning movement about an axis parallel to that of said rotary crank and said rocking lever having a free end portion distant from said one end thereof; linkage means pivotally connected to said rotary crank means and to said rocking lever at said free end portion thereof for turning said rocking lever in an opening direction during turning of said crank means in said door-opening direction and in an opposite closing direction during turning of said crank means in said door-closing direction; an elongated coil spring connected at one end also said free end portion of said rocking lever and at an opposed end to said housing, said spring being tensioned during turning of rocking lever in said opening direction whereby said spring urges said rocking lever to turn in said closing direction to act through said linkage means on said crank means for turning the latter in said door-closing direction after the door is opened; and elongated damping means for damping the turning of said lever in said closing direction by said spring, said damping means being carried by said housing and extending alongside of and closely adjacent to said spring and said damping means being connected to said rocking lever between the ends thereof closer to the turning axis of said lever than said iree end portion thereof.

6. A door closer as recited in claim and wherein said necking lever has a pair of spaced parallel webs carrying a pin at said free end portion of said rocking lever and said coil spring as well as said linkage means being connected to said pin, said damping means being connected to said rocking lever between the webs thereof.

7. An automatic door closer comprising, in combination, housing means; rotary crank means supported for rotation about its axis by said housing means and turning in a door opening direction from a rest position through approximately 180 during substantially full opening of a door which is adapted to be connected to said crank means and in an opposite door-closing direction to approximately 180 during closing of a fully-opened door; an elongated rocking lever pivotally connected at one end thereof to said housing means for turning movement about an axis parallel to that of said crank means, said lever having a free end portion distant (from said one end thereof; an elongated coil spring connected at one end to said free end port-ion of said rocking lever and at an opposite end to said housing; elongated damping means extending alongside of and located closely adjacent to said spring, connected to said housing, and connected to said lever intermediate the ends thereof at a location closer to the turning axis of said lever than said free end portion thereof; and elongated toggle linkage means connected to said crarnk means and said rocking lever said toggle linkage means including a pair of links pivotally connected to each other and respectively connected pivotally at free end portions distant from their pivotal conneotion to each other to said crank means and said rocking lever, said toggle linkage means having an approximately dead-center position when said crank means is in said rest position thereof and said crank means turning said links of said linkage means to one side of said dead center position thereof during turning of said crank means in said door-opening direction, said linkage means turning said rocking lever in a direction which tensions said coil spring during turning of said crank means in said door-opening direction, so that when the door is released said spring means will turn said rocking lever in an opposite direction where said rocking lever will act through said linkage means on said crank means to turn the latter in said door-closing direction, and said toggle linkage means duning turning of said crank means in said doorclosing direction moving back to said dead-center position thereof and tending to move through said .dead-center position thereof to the other side of said dead-center position, one of said links carrying a stop portion which engages the other of said links to limit the movement of said toggle linkage means through said dead center position thereof to said other side thereof during closing of the door, whereby the opposition to the door closing provided by said damping means will not displace said toggle linkage means substantially beyond said dead-center position thereof to the other side of said dead center position.

8. A door closer as recited in claim 7 and wherein said housing means includes a wall portion located adjacent to said toggle linkage means for limiting the movement thereof to said one side of said dead-center position thereof, whereby if said toggle linkage means should lit move to an undesirable extent to said one side of said dead-center position thereof said housing means will engage the toggle linkage means and limit such movement thereof.

9. A door closer as recited in claim 7 and wherein said crank means has a pair of webs and crank pin extending therebetween and wherein one of said links is pivotally connected to the latter pin between the webs of said crank means, the other of said links including a pair of parallel webs which are connected to said rocking lever.

10. A door closer as recited in claim 9 and wherein at least one of said webs of said link connected to said rocking lever carries said stop portion which cooperates with the other link.

11. An automatic door closer comprising, in combination, housing means; rotary crank means supported for rotation about its axis by said housing means and adapted to be connected to a door for turning movement from a predetermined rest position in a door-opening direction during opening of the door and in an opposite door-closing direction back to said rest position during closing of the door; an elongated rocking lever turnably connected at one end thereof to said housing means for turning movement about an axis parallel to the axis of said rotary crank means, said lever having a free end portion distant from the connection of said lever to said housing means; elongated linkage means connected at one end to said crank means and at an opposite end to said rocking lever and extending along an axis which makes an angle of approximately 45 with said rocking lever when said crank means is in said rest position, said crank means acting through said linkage means on said lever to turn the latter in an opening direction during turning of said crank means in said door-opening direction and in an opposite closing direction during turning of said crank means in said door-closing direction; an elongated coil spring connected at one end to said free end portion of said rocking lever and at an opposite end to said housing, said spring being tensioned during turnin of said rocking lever in said opening direction so that upon release of the door said spring will turn said lever in said closing direction to act through said linkage means on said crank means to turn the latter in said door-closing direction; and elongated damping means carried by said housing and connected to said rocking lever intermediate the ends thereof closer to the turning axis of said lever than said free end portion thereof, said damping means resisting the turning of said rocking lever in said closing direction.

12. A door closer as recited in claim 11 and wherein in the rest position of said crank means said rocking; lever makes an angle of approximately with an elongated axis along which said coil spring extends as well as with an elongated axis along which said damping means extends, the latter being substantially parallel to said coil spring.

13. An automatic door closer comprising, in combination, housing; rotary crank means supported for rotation about its axis by said housing means and being adapted to be connected to a door for turning movement from a given rest position in a door opening direction during opening of the door and in an opposite door-closing dircction back to said rest position during closing of the door; an elongated rocking lever pivotally connected at one end thereof to said housing means for turning movement about an axis parallel to that of said crank means and having a free end portion distant from said one end thereof; elongated linkage means connected at one end to said crank means and at an opposite end to said lever for turning said lever in an opening direction during turning of said crank means in said door-opening direction and in an opposite closing direction during turning of said crank means in said door-closing direction; releasable holding 11 means carried by said housing means and cooperating with said linkage means for reieasahly holding said door in at least one predetermined open position; an elongated coil spring connected at one end to said free end portion of said lever and at an opposite end to said housing, said coil spring being tensioned during turning of said lever and said opening direction so as to urge said lever in said opposite closing direction to act through said lever and said linkage means on said crank means for closing the door after it is opened; and damping means carried by said housing means and operatively connected to said lever intermediate the ends thereof closer to the turning axis of said lever than said free end portion thereof for yieldably resisting turning of said lever by said spring means in said closing direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,101,232 Adams June 23, 1914 2,223,045 Pariot Nov. 6, 1940 2,962,749 Sasse Dec. 6, 1960 2,971,212 Voster et al Feb. 14, 1961 

1. AN AUTOMATIC DOOR CLOSER COMPRISING, IN COMBINATION, HOUSING MEANS; ROTARY CRANK MEANS SUPPORTED FOR ROTATION ABOUT ITS AXIS BY SAID HOUSING MEANS, SAID CRANK MEANS BEING ADAPTED TO BE CONNECTED TO A DOOR AND TURNING IN A DOOR-OPENING DIRECTION DURING OPENING OF THE DOOR AND IN A DOOR-CLOSING DIRECTION DURING CLOSING OF THE DOOR; AN ELONGATED ROCKING LEVER PIVOTALLY CARRIED ADJACENT ONE END THEREOF BY SAID HOUSING MEANS FOR TURNING MOVEMENT ABOUT AN AXIS PARALLEL TO THAT OF SAID ROTARY CRANK MEANS, SAID ROCKING LEVER HAVING A FREE END PORTION DISTANT FROM SAID ONE END THEREOF CONNECTED TO SAID HOUSING MEANS; LINKAGE MEANS CONNECTED AT ONE END TO SAID ROTARY CRANK MEANS AND AT AN OPPOSITE END TO SAID ROCKING LEVER FOR TURNING THE LATTER IN AN OPENING DIRECTION DURING TURNING OF SAID CRANK MEANS IN SAID DOOR-OPENING DIRECTION AND IN A CLOSING DIRECTION DURING TURNING OF SAID CRANK MEANS IN SAID DOOR-CLOSING DIRECTION; AN ELONGATED COIL SPRING CONNECTED TO ONE END TO SAID ROCKING LEVER AT SAID FREE END PORTION THEREOF AND AT AN OPPOSITE END TO SAID HOUSING MEANS AND SAID COIL SPRING BEING TENSIONED DURING TURNING OF SAID LEVER IN SAID OPENING DIRECTION SO THAT SAID COIL SPRING URGES SAID ROCKING LEVER TO TURN IN SAID CLOSING DIRECTION TO ACT THROUGH SAID LINKAGE MEANS ON SAID CRANK MEANS FOR URGING THE LATTER TO TURN IN SAID DOOR-CLOSING DIRECTION AFTER THE DOOR IS OPENED; AND ELONGATED DAMPING MEANS FOR DAMPING THE CLOSING OF THE DOOR BY SAID COIL SPRING, SAID ELONGATED DAMPING MEANS BEING LOCATED ALONGSIDE OF AND CLOSELY ADJACENT TO SAID COIL SPRING, BEING PIVOTALLY CONNECTED TO SAID ROCKING LEVER BETWEEN THE ENDS THEREOF SO THAT THE COIL SPRING IS CONNECTED TO SAID ROCKING LEVER AT A LOCATION MORE DISTANT FROM THE TURNING AXIS THEREOF THAN SAID DAMPING MEANS, AND SAID DAMPING MEANS BEING CONNECTED TO SAID HOUSING MEANS AT A PART OF SAID DAMPING MEANS SPACED FROM SAID ROCKING LEVER. 